1. Technical Field
The present invention relates to a disk enclosure having large data storage capacity, and more particularly to a large capacity disk enclosure that is capable of performing management properly and easily.
2. Description of the Related Art
Information storage devices are typically required to have large storage capacity and to allow high-speed access. It is also desired that they allow stored data to be shared by users at remote places. With respect to these requirements, a data storage system 1, schematically shown in FIG. 7, is employed as an information storage system. The data storage system 1 shown in FIG. 7 includes a host system 2, one or more disk enclosures 3, and FC-AL (Fibre Channel-Arbitrated Loop) 5 connected to the host system 2. Each disk enclosure 3 includes a plurality of hard disk drives (HDDs) 6 that function as nodes of the FC-AL 5. In FIG. 7, for the sake of simplicity, only one HDD 6 is shown and the other HDDs 6 are omitted.
The data storage system 1 can realize large storage capacity by incorporating a plurality of such disk enclosures 3. Employing the FC-AL 5, the data storage system 1 can realize a high data transfer rate and thereby allows high-speed access. Further, as shown in FIG. 8, a storage area network 12 can be formed by connecting, as servers 10, the host systems 2 to the disk enclosure 3 and a RAID controller 61 through a hub 8 and a switch 9. In this manner, local area networks each of which is formed by the servers 10 and terminals 13 can be separated from a storage network to and from which the servers 10 write and read data, whereby the network traffic can be made more efficient and a plurality of servers are allowed to share the storage.
As shown in FIG. 7, in the data storage system 1, each disk enclosure 3 is provided with an enclosure manager 14. For example, as schematically shown in FIG. 9, the enclosure manager 14 is connected to predetermined HDDs 6 of the disk enclosure 3 through a parallel ESI (Enclosure Service Interface) buses 15 and can communicate with the host system 2 through a controller of the HDD 6 using SCSI (Small Computer System Interface) commands, specifically, SCSI enclosure service commands (SES commands).
The enclosure manager 14 responds to a request (SES command) from the host system 2 to send internal temperature of the disk enclosure 3, failure location therein, and other control and management information to the host system 2 through the controller of the HDD 6 and the FC-AL 5, and control the disk enclosure 3 properly through internal loop control and other control for the disk enclosure 3.
However, the data storage system 1 using such disk enclosures 3 has the following problems. The data storage system 1 employs the parallel ESI bus 15 for communication of plural kinds of data between the enclosure manager 14 and the HDDs 6. Since the ESI scheme defines peer-to-peer communications, it is necessary to provide the parallel ESI bus 15 between the enclosure manager 14 and every HDD 6 to enable communications between the enclosure manager 14 and the plural HDDs 6 according to the ESI scheme. This necessitates providing many signal lines between the enclosure manager 14 and the HDDs 6, which is virtually impossible. Therefore, among the disk slots 16 (see FIG. 9) to which the HDDs 6 can be attached in the disk enclosure 3, two or three particular slots are generally defined as such disk slots 16′ that the HDD 6 attached thereto can be connected to the parallel ESI bus 15. However, in this case, if the HDDs 6 are not attached to the particular disk slots 16′, the disk enclosure 3 cannot be controlled or managed according to the ESI scheme, which makes it difficult to perform data management properly. Further, to control and manage the disk enclosure 3 properly, it is necessary to instruct a user to have the ESI-supporting disk slots 16′ always mounted with HDDs 6, which would cause inconvenience to the user.